Idler pulley



June lo .Y HfF. .ARNOI- VDA v I l IDLER PULLEY. y v

Filed Agg, 21, 192e. 2 ,sheets-snee; 2

/fwevzzop f/ W ,Z4/WMM., LL; a' f 1 Patented June l0, 193,0`

v justment off` the pulley to' determine .the initial belt tension.

moving in a substantially recti1inearpath,

' the arrow ,(Fig.

`mode of attachingthe device'to i Referring more in vbetween the arms 2 HENRY F. ARNOLD, or HYDE PARK,

MASSACHUSETTS, ASsIGNon 'ro AMERroANjmoon & MACHINE COMPANY, oFBosroN, MAssAcHUsETTs, A conPonA'rroN or MAssA- "CHUSETTS,

Y Applqaiipii The present invention relates to idler pulleys for belttensioning and more particularly toa form of idler pulley particularly adapted vautomatically to tighten a belt while it is being driven and. to maintain a predef mined tension thereon. Y v c In accordance withthe presentv invention the'tensioning` force is so applied as gradually to increase in'effe'c'tive'value as thepulley moves in response thereto, thustighteni'ng'V the belt in avery certainy and reliable manner, provision being made for manual ad- The invention vis herein disclosed as Iembodied in a construction/1n which the idlerpulley is carried by a support although in its broader aspects the invention is not necessarily restricted to this arrange-V ment."

In the accompanying drawings, a preferred embodimentof the invention is illustrated, in Which: r l y f Fig.4 1 is a view in elevation of myinvention,` a part being broken away to show the a beamv or other supporting means; and r Fig. 2 isa side elevation ofthe device, partly in section. Y

the numeral 1 indicates anpulley or idler of the usual form which may be supportedby arms 2 and 3, or other holding means. In'

order to render Athe pulley movable I preferably connect the arms 2 and?) to a supporting member 4,. which ing member 5 as to be a direction to tighten a belt. y(

In the drawings aL belt '6? is shownv passing slidable Vor Vmovable in of which passes inthe direction indicated by thelower section of the belt passing over the pulley 1` in the opposite direction, being then delivered to a belt-driving pulley or a driven pulley, for example. 'The belt may obviously bedriven' by means of any suitable source of power and may be composed yof leather Yor other desired composition. l

The pulley 1 is preferably mounted insuch `integral therewith.

rmeans of bolts and-nuts daan to the drawings,

'rection to increase ,with the pulley so that is so mounted in a hold-1 position ofthe weight. 'toggle lever is preferably means of stationary.support 18which maybe and '3 the upper section bifurcated, and to which the arm may be pivl 2)- to the devicetobel driven,

. connected yto the arm IDLER PULLEY mea August 21, 192e. Y' serial Naiaoeei;

a way vas to move in a rectilinear path in; a`

horizontal plane,

be changed, depend- I although the path of movevm-ent of thepulley. may

ing upon the direction of movement or'inclination of the driven belt.k The arms`2 and. 3 may be connected to by bolts or other fastening means, ormaybe The member 4' preferably comprises side members 6 and 7 adapted. to slide in grooves 8 and-'9 formed in side 'arms 10 and 11 of `thermember 5,', which arms eX- tend downwardly so as to envelope' the .side members 6 and 7 By the movement ofthe members 6 and/7, in the grooves 8 and 9, the path of movement pulley l'connectedv thereto is determined.

The tensioning mechanism is' preferably supported by suitably attaching the member means,

suitable fastening means. Y

In order to move the Vmember 4 and the pulley attached thereto so as to cause a predetermined tensionin the belt .6', I preferably` provide a weight lmember V15 which maybe of any suitable.V size `depending" upon the amount offorce which is desired to be appliedl and so mount the weight inVV relation to theV f ulleymember'as to multiply the force ap:

Yplied thereby, asfthe pulley moves in a d1- the tension-on the belt.` y In order toaccomplish this result l prefer. Y lever 16in connection ably mount` aV toggle as the weight is moved of the'member 4 and the the member 4 if desired',

erf

5 to'a beam12 or other suitable supporting the member being attachedltheretozbyl. 13 y andf14lvor other downwardly the toggle opens outwardly so as to exert the maximum One arm'l'? of the otally 'connected in any suitable way. Thev held at one end-by force'in thelowered f other arm 19k of the toggleVV lever is pivotally i' 17 and to a movable lever 20 whichis operatively connected to the pulley member..` One end'lof the lever 2O kis connected to a fixedl stationary support 21,

which is preferably bifurcated so as to hold n the lever 2O between its arms, and issupportedby the member 5 orotherfstationary' 1. iov

support. The other end of the lever is preferably connected to the pulley supporting member 4 by means of an adjustable connection, such as screw-threaded rod 22 adapted to be turned relatively to the lever 20. A nut or other threaded member 23 is connected to the m-ember 4 and is mounted on the rod 22 whereby, when the rod 22 is turned relative to the nut, the latter is movedl along the rod,.and the position of the pulley may therefore be adjusted to attain any desired degree of tension in the belt within certain limits.

"mounted with respect to the l'as the weight 15 moves downwardly against -the members 24, 25 being position, being mounted on the stationary The weight member 15 is preferably mounted upon stationary guide members 24, 25 in such a manner as to be slidable thereon, preferably fixed in beam.12, or attached to the stationary member 5. The toggle lever is preferably proor may be so vided with a stop member, e

beam l2 that the toggle joint, the toggle is not opened to its full open position but comes into con- Vtact with the beam 12 as indicated in dotted "by turning` the screw rod 22 so. as to attain rlhe rod is preferably adthe position in which the the desired set. justed sothat `in vweight 15 has moved downwardly to where the toggle lever has moved against its stops,

the force :eXertedby the pulley against the belt will be the maximum desired tension.

As the belt stretches-or if the tension exerted by the belt changes, theV toggle leverl will move in a direction to compensate for the change. .If-the tension inthe belt should decrease for example, the weight 15 would move downwardly forcing the toggle lever .into a moreopen .position whereby the end of the arm 19 in Contact with the lever 20 would move to the lright forcing the lower endl thereof, which is in contact with the rod to the right also, andthe nut 23 attached tojlthe rod 22 and to the .pulley supporting member 4 would also be moved to the right whereby the pulley 1 would also move in the `'same direction thereby causing increased tension inthe belt.

It is to be understood that the device which has been described constitutes the preferred form of the invention, and that various changes or modifications may be made Vtherein without departing from the spirit or scope of the invention as defined in the claims.

"I claim: f `f 'l 1. In a device of the kind described, a bodily movable pulley, a toggle lever including two links connected in a. cent-ral joint and operatively connected to said pulley to provide movement thereof, and means for applying a force to said joint of the toggle lever whereby the said pulley will be moved with a force in accordance with the leverage in the position assumed by the toggle.

2. In an automatic belt tightener the combination of a pulley, movable means for supporting the pulley, means for moving the said supporting means and said pulley in a rectilinear path comprising a toggle lever one link of which is operatively connected to said supporting means and the other link of which is attached to a stationary support, means for applying a force to the connection between said links of said toggle lever so as to move said pulley in a direction t0 tighten a belt and means for .adjusting the relative position of said pulley and supporting means with respect to saidmoving means.

3. In an automatic belt tightener the combination of a belt engaging.idler-pulley, a slidable support therefor, a weight member, a toggle lever comprising a pair of links having a joint therebetween operatively connected to said slidable support, and means for applying the weight of sail weight member to the joint of said toggle lever to move the pulley in a direction to maintain tension in a belt. l

4. In an automatic belt tightener a pulley, a stationary member having a guideway thereon, a movable supporting means for said pulley adapted to move in said 'guideway, a weight member, a toggle lever operatively connected to said. movable supporting means, and means for applying the weight to the joint of the toggle lever, whereby the toggle lever will apply an increasing force to said supporting means as the pulley is moved in a direction correspondingy to the open position of the toggle lever.

5. In an automatic belt tightener, the combination of a. pulley, a movable support for said pulley, a holding member for said support having ay guideway therein adapted to permit sliding movement of said movable support. a toggle lever pivoted at one end to a stationary support and operatively connected at its other end to said movable support, means for relatively adjusting the position of said support with respect to said toggle lever, a weight member, guide means for said weight member adapted to apply the weight to substantially the joint of the toggle, and stop means for said toggle to prevent movement thereof to its full open position.

Signed by me at Boston, Massachusetts, this s'izteenth day of August, 1926. j

HENRY F. ARNOLD. 

